As many as one in 20 Covid-19 hospital patients remain infectious after two weeks, according to secret advice papers published today.
SAGE scientists warned the Government on May 28 that around 5 per cent of very unwell virus patients, mostly elderly people, can infect others for up to 20 days.
They said this poses a ‘risk for onwards transmission to carers’, care home workers and family members who may then go and pass the disease onto others.
Currently Britons with the disease are told to self-isolate for a maximum of 14 days, as that’s when the virus clears in most people.
One of the scientific reports presented to ministers earlier this month also revealed the Government’s top experts still don’t know how accurate Covid-19 swab tests are.
SAGE experts admitted there was a dearth of research looking into how often the swabs – considered the gold standard of Covid testing – give false negatives.
A review of previous studies on the PCR tests suggest one in five infected people get a faulty result, despite having experienced three days of symptoms.
The Government was also warned that without a test and trace system that caught 80 per cent of cases within 48 hours, opening schools would cause the reproduction ‘R’ number to soar.
Some 31 documents were today published by the Government Office for Science, which is headed by Sir Patrick Vallance, England’s chief scientific adviser.
The SAGE papers are being released in a bid to show greater transparency from the Government.
They are among dozens in a tranche of papers presented to SAGE, the Government’s Scientific Advisory Group for Emergencies, over recent months to help guide ministers through the crisis.
And the reports detail all the scientific advice which is being presented to decision-making officials who dictate when and how the country moves out of lockdown.
Files released today revealed scientists told the Government:
- A YouGov poll on March 17 found more than half (55 per cent) of Brits were still going to bars pubs and restaurants and six in 10 were still seeing family members and friends from other households, despite Government guidance advising not to;
- NHS antibody testing scheme suggest 16 per cent of staff have had coronavirus and a FIFTH of hospital patients have recovered from the virus;
- The Government has been warned since April 20 that taxi drivers and factory workers are among the most at-risk occupations for catching the disease;
- SAGE experts admitted it still doesn’t know how often the Covid-19 swabs rolled out nationally in the UK give false negatives;
- Prisons, migrant centres, long stay mental health hospitals and homeless shelters could be potential Covid-19 breeding grounds in the future;
- The Government has been told that coronavirus health messages tailored specifically for different ethnic groups are ‘particularly important’.
SAGE scientists warned that, without a test and trace system that caught 80 per cent of cases within 48 hours, the R would soar above one (shown left, if test and trace worked just 20 per cent of the time, compared to 80 per cent, right)
One in 20 hospitalised patients may be infectious beyond 14 days
About 5 per cent of patients ill enough with coronavirus to be admitted to hospital are contagious to others after two weeks, two separate SAGE reports found.
Two teams of Government scientists submitted papers to ministers on May 28 warning some sufferers had high enough viral load to infect others for 20 days.
They reviewed the available evidence from around the world looking into viral load in hospitalised patients with the disease, as well as new UK research on British patients.
The team of virologists and infectious disease experts – which included Professor Peter Horby, an epidemiologist from Oxford University – found most people are not infectious 12 days after symptoms started.
Samples from the upper respiratory tract of 74 Covid patients in the UK showed viral load was picked up after 20 days in some patients
‘However, a very small minority of hospitalised individuals might remain infectious until day 20’, they write, adding that many of these patients will be elderly.
They warned that this finding poses a ‘risk for onwards transmission to carers’, care home workers and family members who may then go and pass the disease onto others.
The scientists recommended that people working in high risk areas like care homes, as well as care home residents themselves, be given swab and antibody tests after recovering from the virus before returning.
A high level of antibodies in the blood ‘is likely to correlate with a low probability of infectiousness’, the researchers say.
Accuracy of coronavirus PCR swab tests is still not fully understood
The swab tests currently being used in the UK to diagnose coronavirus can miss infected people up to a fifth of the time, accoring to a paper submitted to ministers this month.
The UK’s Covid-19 testing programme uses a network of laboratories to detect SARS-CoV-2 in nasopharyngeal swabs, which take samples from the throat and nose.
SAGE researchers said these swabs – the gold standard of testing currently- are 95 per cent sensitive and specific.
This means that, under laboratory settings, they are correct more than nine times out of 10.
But errors in the way samples are collected in the community and transported to laboratories can bring down their accuracy significantly.
A model used by SAGE scientists shows the likelihood of a swab giving a false negative is lowest between day five and day 10 of infection of symptoms
For this reason, ‘the UK operational false positive rate is unknown’, the experts said, and ‘there are no published studies on the operational false positive rate of any national COVID-19 testing programme.’
They used a model which combined results from seven studies and more than 1,300 swab tests to create a model of the the false negative rate for the test.
The model suggested that in the first four days of infection, when a patient is pre-symptomatic, the tests can give a false positive up to 67 per cent of the time.
This is because the virus has not yet had time to duplicate inside their respiratory system, making it hard to pick up by the test.
The chance of a false negative then dropped to 38 per cent on day 5 – the day when most people get symptoms.
By day eight, the tests were 80 per cent accurate, meaning they gave a false negative one in five times to people who had symptoms for at least three days.
The researchers recommended the Government launches an independent quality assessment review of the testing programme to make sure its fit for purpose.
They also said negative results that allow people to return to work, leave hospital or come out of isolation should be ‘treated with extreme caution’.
These people should self-isolate for 14 days regardless of the test result, the experts advised.
More than half of Brits ignored PM’s plea to avoid pubs and bars
Boris Johnson’s plea for Britons to stay away from pubs, bars and restaurants in mid-March fell on deaf ears, a poll submitted to SAGE revealed.
A YouGov survey between March 17 and 18, a week before lockdown, showed more than half (55 per cent) of adults were still eating and drinking out.
Forty-five per cent said they’d stopped altogether and 17 per cent said they’d reduced the amount of times they attended the establishments.
Mr Johnson was adamant not to put the UK into lockdown, as the rest of Europe had at the time, and instead tried to use public messaging on social distancing and hand washing in early March to curb the spread.
But the YouGov poll, along with alarming predictions that hundreds of thousands of people would die from the virus, forced him to impose the nationwide quarantine.
The survey also found that just 27 per cent of people stopped seeing family from other households.
Just over a third (35 per cent) of the public, and more than half (59 per cent) of full-time workers were still going to work as often as before.
Only 16 per cent of children had stopped going to school by March 18.
Ministers must tailor health messages to people from BAME groups
The Government has been told that coronavirus health messages tailored specifically for different ethnic groups are ‘particularly important’.
Ministers were recommended to give people from BAME backgrounds – who are disproportionately affected by the virus – extra advice on how to stay safe during the crisis.
The advice is outlined in a summary of a discussion on ethnicity and Covid-19 risk, endorsed SAGE on June 4.
The Sage summary said: ‘Work was discussed that highlighted the importance of faith practices, differences in patterns of healthcare usage, willingness of communities to engage with prevention, and other factors such as access to outdoor space.
‘Different messaging, including health messages tailored specifically for different ethnic groups was highlighted as being particularly important.’
Two reports have been published by Public Health England (PHE) in recent weeks which suggested BAME communities are dying from Covid-19 at greater rates than people in white ethnic groups.
The earlier findings from PHE said that people of Bangladeshi heritage were dying at around twice the rate of white Britons.
It also found that other minority ethnic groups were at up to 50 per cent higher risk of dying.
The second report pointed to a raft of recommendations from stakeholders, including the need to develop ‘occupational risk assessment tools that can be employed in a variety of occupational settings and used to reduce the risk of employee’s exposure to and acquisition of Covid-19’.
This is especially true for BAME workers in health and social care and on the front line in occupations that put them at higher risk, it said.